From 91a7221964e32ec4f727e7be5ee892b451affe28 Mon Sep 17 00:00:00 2001
From: Costa Tsaousis <costa@tsaousis.gr>
Date: Sat, 30 Apr 2016 14:36:38 +0300
Subject: [PATCH] support for newer kernels that show cgroups mountinfo at
 super_options

---
 src/proc_self_mountinfo.c | 39 +++++++++++++++++++++++++++++++++++++--
 src/proc_self_mountinfo.h |  1 +
 src/sys_fs_cgroup.c       |  3 +++
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/src/proc_self_mountinfo.c b/src/proc_self_mountinfo.c
index fa407967..a2a9e09a 100644
--- a/src/proc_self_mountinfo.c
+++ b/src/proc_self_mountinfo.c
@@ -33,13 +33,48 @@ struct mountinfo *mountinfo_find_by_filesystem_mount_source(struct mountinfo *ro
 	uint32_t filesystem_hash = simple_hash(filesystem), mount_source_hash = simple_hash(mount_source);
 
 	for(mi = root; mi ; mi = mi->next)
-		if(mi->filesystem_hash == filesystem_hash && mi->mount_source_hash == mount_source_hash
-				&& !strcmp(mi->filesystem, filesystem) && !strcmp(mi->mount_source, mount_source))
+		if(mi->filesystem
+		   		&& mi->mount_source
+				&& mi->filesystem_hash == filesystem_hash
+		   		&& mi->mount_source_hash == mount_source_hash
+				&& !strcmp(mi->filesystem, filesystem)
+		   		&& !strcmp(mi->mount_source, mount_source))
 			return mi;
 
 	return NULL;
 }
 
+struct mountinfo *mountinfo_find_by_filesystem_super_option(struct mountinfo *root, const char *filesystem, const char *super_options) {
+	struct mountinfo *mi;
+	uint32_t filesystem_hash = simple_hash(filesystem);
+
+	size_t solen = strlen(super_options);
+
+	for(mi = root; mi ; mi = mi->next)
+		if(mi->filesystem
+		   		&& mi->super_options
+				&& mi->filesystem_hash == filesystem_hash
+		   		&& !strcmp(mi->filesystem, filesystem)) {
+
+			// super_options is a comma separated list
+			char *s = mi->super_options, *e;
+			while(*s) {
+				e = ++s;
+				while(*e && *e != ',') e++;
+
+				size_t len = e - s;
+				if(len == solen && !strncmp(s, super_options, len))
+					return mi;
+
+				if(*e == ',') s = ++e;
+				else s = e;
+			}
+		}
+
+	return NULL;
+}
+
+
 // free a linked list of mountinfo structures
 void mountinfo_free(struct mountinfo *mi) {
 	if(unlikely(!mi))
diff --git a/src/proc_self_mountinfo.h b/src/proc_self_mountinfo.h
index 8c212749..51712a58 100644
--- a/src/proc_self_mountinfo.h
+++ b/src/proc_self_mountinfo.h
@@ -34,6 +34,7 @@ struct mountinfo {
 
 extern struct mountinfo *mountinfo_find(struct mountinfo *root, unsigned long major, unsigned long minor);
 extern struct mountinfo *mountinfo_find_by_filesystem_mount_source(struct mountinfo *root, const char *filesystem, const char *mount_source);
+extern struct mountinfo *mountinfo_find_by_filesystem_super_option(struct mountinfo *root, const char *filesystem, const char *super_options);
 
 extern void mountinfo_free(struct mountinfo *mi);
 extern struct mountinfo *mountinfo_read();
diff --git a/src/sys_fs_cgroup.c b/src/sys_fs_cgroup.c
index fbaf1318..6c2fdb03 100644
--- a/src/sys_fs_cgroup.c
+++ b/src/sys_fs_cgroup.c
@@ -47,18 +47,21 @@ void read_cgroup_plugin_configuration() {
 	struct mountinfo *mi, *root = mountinfo_read();
 
 	mi = mountinfo_find_by_filesystem_mount_source(root, "cgroup", "cpuacct");
+	if(!mi) mi = mountinfo_find_by_filesystem_super_option(root, "cgroup", "cpuacct");
 	if(!mi) s = "/sys/fs/cgroup/cpuacct";
 	else s = mi->mount_point;
 	snprintf(filename, FILENAME_MAX, "%s%s", global_host_prefix, s);
 	cgroup_cpuacct_base = config_get("plugin:cgroups", "path to /sys/fs/cgroup/cpuacct", filename);
 
 	mi = mountinfo_find_by_filesystem_mount_source(root, "cgroup", "blkio");
+	if(!mi) mi = mountinfo_find_by_filesystem_super_option(root, "cgroup", "blkio");
 	if(!mi) s = "/sys/fs/cgroup/blkio";
 	else s = mi->mount_point;
 	snprintf(filename, FILENAME_MAX, "%s%s", global_host_prefix, s);
 	cgroup_blkio_base = config_get("plugin:cgroups", "path to /sys/fs/cgroup/blkio", filename);
 
 	mi = mountinfo_find_by_filesystem_mount_source(root, "cgroup", "memory");
+	if(!mi) mi = mountinfo_find_by_filesystem_super_option(root, "cgroup", "memory");
 	if(!mi) s = "/sys/fs/cgroup/memory";
 	else s = mi->mount_point;
 	snprintf(filename, FILENAME_MAX, "%s%s", global_host_prefix, s);
-- 
2.39.2